What would you consider normal compression readings for a 1989 5.0L engine. My readings run between 105 and 120. Would these be within normal range. My Chilton manual says all should be within 20% of highest reading with no reading below 100. Does not say what standard should be. Does this sound right?

Thanks in advance.
God Bless
Whisler

 

Doesn't anyone have an idea what the compression readings should be on a good 5.0L engine?

God Bless
Whisler

 

I see by your post count that you are fairly new to FTE and I welcome you. Just a suggestion that sometimes you can get a faster answer to most questions by doing a search as in "compression readings" at the right top of the page and will turn up a world of information as most questions have been discussed prior.

But, to try to answer your question, 140 lbs is good and 150 lbs would be really good. Compression check should be done with all plugs removed and WOT to get an accurate reading. If any cylinder(s) are reading low you may want to squirt a little oil in and re test. If the compression rises much it would indicate excessive ring wear. Otherwise it could indicate valve leakage.

Hope this helps you in some way and I encourage you to participate as there is lots of knowledge here.

 

Thanks for your reply. I did a search originally but my search techniques leave a lot to be desired. I just put in "normal copression readings' and got about 5 threads, none of which did me much good.
God bless
Whisler